Linear Compressor Bearing Refrigerant Passage for Heat Isolation

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Solution Overview

Problem

In linear compressors, high-temperature refrigerant flowing into the gas hole from the discharge unit transfers heat to the frame and subsequently to the piston and cylinder, leading to overheating of the suction refrigerant and reduced compression efficiency due to heat conduction.

Innovation Solution

A discharge plenum is integrated into the discharge cover, with a bearing refrigerant passage extending directly to the gas hole, allowing the refrigerant to flow as a bearing refrigerant at the shortest distance, minimizing heat transfer by reducing contact between the high-temperature refrigerant and the frame, and using a bearing refrigerant pipe or hole to facilitate this flow.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If the high-temperature refrigerant flows from the discharge unit through the frame to the gas hole, then the refrigerant can be transferred to the bearing, but the heat is transferred to the frame, piston and cylinder, overheating the suction refrigerant and reducing compression efficiency

Engineering Contradiction:
Improverefrigerant flow to bearingVSAvoidsuction refrigerant temperature
Core Design Contradiction:
Quantity of substanceVSTemperature

Solution Approach 1:

The patent segments the refrigerant flow path into two separate channels: one for high-temperature discharge refrigerant flow (through the discharge unit) and another for low-temperature bearing refrigerant flow (directly from the suction side through the bearing refrigerant hole to the gas hole). This segmentation allows the bearing to receive cooled refrigerant while the discharge refrigerant takes a separate path, preventing heat transfer to the frame and piston.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The bearing refrigerant hole acts as an intermediary channel that directly connects the suction side to the gas hole, bypassing the frame and discharge unit. This intermediary path enables the bearing to receive refrigerant at suction temperature without being exposed to the high-temperature discharge refrigerant, thus preventing overheating while maintaining proper lubrication.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Quantity of substance

If the bearing refrigerant flows along the front surface of the frame to reach the gas hole, then the refrigerant can be supplied, but the high-temperature refrigerant transfers heat to the frame which then conducts heat to the piston and cylinder

Engineering Contradiction:
Improvebearing refrigerant supplyVSAvoidheat transfer to frame
Core Design Contradiction:
Quantity of substanceVSLoss of energy

Solution Approach 1:

The patent extracts the bearing refrigerant supply path from the frame structure by creating a dedicated bearing refrigerant hole that bypasses the frame entirely. The bearing refrigerant flows directly from the suction side through this hole to the gas hole, taking out the harmful heat transfer pathway and eliminating the energy loss through frame conduction.

Inventive Principle:
Principle #2Taking out (Extraction)

3Stability of the object's composition

If the discharge cover is in close contact with the frame, then structural stability is improved, but heat from the discharge cover is conducted to the frame and transferred to the piston and cylinder

Engineering Contradiction:
Improvestructural stabilityVSAvoidframe temperature
Core Design Contradiction:
Stability of the object's compositionVSTemperature

Solution Approach 1:

The patent applies local quality by creating a localized thermal barrier between the discharge cover and the frame. The bearing refrigerant hole and the separate flow paths create a local region where cooling occurs, while the discharge cover maintains its thermal isolation from the frame in the critical areas, allowing structural stability while preventing heat conduction to the piston and cylinder.

Inventive Principle:
Principle #3Local quality

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This configuration reduces heat transfer to the cylinder and piston, maintaining the suction refrigerant at a lower temperature and enhancing compression efficiency by minimizing direct contact between high-temperature refrigerant and the frame, thus improving overall compressor performance.

Implementation Method 1

a bearing refrigerant passage extending toward the gas hole so that a portion of the refrigerant flowing into the discharge space flows into the gas hole

Methodology Applied
Scientific EffectFluid flow:

Implementation Method 2

high-temperature refrigerant compressed in a compression space. The refrigerant transferred from the discharge unit to the frame side flows along a front surface of the frame to flow into the gas hole. That is, there is a limitation in that the high-temperature refrigerant flows between the discharge unit and the frame to transfer heat to the frame

Methodology Applied
Scientific EffectHeat conduction: Conduction (thermal)

Implementation Method 3

as the heat is transferred from the frame to the piston and the cylinder, the suction refrigerant flowing inside the piston is overheated

Methodology Applied
Scientific EffectHeat conduction: Conduction (thermal)

Data Source

PatentEP3808979B1Linear compressor
Publication Date: 2023.11.29 LG ELECTRONICS INC
  • EP3808979B1 patent drawingFigure 1
  • EP3808979B1 patent drawingFigure 2
  • EP3808979B1 patent drawingFigure 3

AI summary

Provided is a linear compressor. The linear compressor according to an embodiment includes a cylinder, a frame, and a discharge unit. The frame includes a discharge frame surface coupled to the discharge unit and a gas hole recessed from the discharge frame surface. The discharge unit includes a bearing refrigerant passage extending toward the gas hole so that a portion of the refrigerant flowing into the discharge space flows into the gas hole.